Seismic fragility and reliability of structures isolated by friction pendulum devices: seismic reliability‐based design (SRBD)          下载免费PDF全文

Paolo Castaldo  Guglielmo Amendola  Bruno Palazzo 《地震工程与结构动力学》2017,46(3):425-446

The paper deals with the seismic reliability of elastic structural systems equipped with friction pendulum isolators (friction pendulum system). The behavior of these systems is analyzed by employing a two‐degree‐of‐freedom model accounting for the superstructure flexibility, whereas the friction pendulum system device behavior is described by adopting a widespread model that considers the variation of the friction coefficient with the velocity. With reference to medium soil condition, the uncertainty in the seismic inputs is taken into account by considering a set of artificial records, obtained through Monte Carlo simulations within the power spectral density method, with different frequency contents and characteristics depending on the soil dynamic parameters and scaled to increasing intensity levels. The sliding friction coefficient at large velocity is also considered as random variable modeled through a uniform probability density function. Incremental dynamic analyses are developed in order to evaluate the probabilities exceeding different limit states related to both r.c. superstructure and isolation level defining the seismic fragility curves through an extensive parametric study carried out for different structural system properties. Finally, considering the seismic hazard curves related to a site near L'Aquila (Italy), the seismic reliability of the r.c. superstructure systems is evaluated, and seismic reliability‐based design abacuses are derived with the aim to define the radius in plan of the friction pendulum devices in function of the structural properties and reliability level expected. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Preliminary results of biomarker responses in zooplankton of brackish environments   总被引：3，自引：0，他引：3  

Fossi MC  Minutoli R  Guglielmo L 《Marine pollution bulletin》2001,42(9):745-748

Zooplankton is an essential component of the food chains of marine and brackish environments. Ecotoxicological risk to zooplankton, evaluated by the biomarker approach, can be used as an early warning signal of risk to the health of marine ecosystems. The aim of this project is to evaluate the application of certain biomarkers in zooplankton. In the present paper, laboratory and field studies were performed with the copepods Acartia margalefi, Acartia latisetosa and the mysid Siriella clausi. Acetylcholinesterase activity (AChE) was determined in homogenates of whole organisms. Mean AChE activity was 10.05 micromol min g(-1) for A. margalefi, 3.30 micromol min g(-1) for A. latisetosa and 79.70 micromol min g(-1) for S. clausi. A. margalefi and S. clausi also showed a linear increase in enzyme activity with increasing concentrations of samples. Preliminary laboratory work was also carried out with specimens of A. latisetosa, which were exposed to an organophosphorus insecticide (parathion). Moderate inhibition of AChE (19%) with respect to controls was observed. AChE activities were two orders of magnitude higher in the zooplankton than in hemolymph samples of the decapod Carcinus aestuarii (Fossi et al., 1996) indicating that these species have a high metabolic rate, which makes them suitable for biomarker studies.  相似文献